Cu–Zn–Cr2O3 Catalysts for Dimethyl Ether Synthesis: Structure and Activity Relationship
Cu–Zn–Cr2O3 Catalysts for Dimethyl Ether Synthesis: Structure and Activity Relationship
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DOI：
10.1007/s10562-008-9408-6
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发表时间：
2008-02
影响因子：
2.8
通讯作者：
A. Venugopal;Jelliarko Palgunadi;K. Jung;O. Joo;C. Shin
中科院分区：
文献类型：
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作者：
A. Venugopal;Jelliarko Palgunadi;K. Jung;O. Joo;C. Shin
以Cu-Zn-Cr类水滑石为前驱体，制备了不同Zn/Cr比的CuO/ZnCr 2 O 4催化剂，采用BET比表面积、XRD、TPR、ESR、N2 O滴定等方法对CuO/ZnCr 2 O 4催化剂进行了表征，并评价了其合成气一步合成二甲醚的活性。结果表明，在高Zn/Cr比时，Cu物种在Cu-ZnO-Cr2 O3上呈高度分散状态，而在低Zn/Cr比时，Cu物种呈团簇状分布。ESR分析显示，由于孤立的Cu 2+在高Zn/Cr比和集群Cu 2+在低Zn/Cr比在新鲜的催化剂和只有Cr 3+物种在使用过的催化剂的信号。TPR结果表明，随着铬含量的增加，还原峰向高温方向移动，这是由于大的铜晶粒的存在，XRD分析支持了这一点。合成气转化为二甲醚的转化率与铜金属的表面积有很好的相关性，表明STD合成可以通过甲醇合成速率来控制。
The CuO dispersed on ZnCr2O4catalysts derived from Cu–Zn–Cr hydrotalcite like layered double hydroxide precursors with varying Zn/Cr ratios have been synthesized, characterized by BET—Surface area, X-ray diffraction (XRD), temperature programmed reduction (TPR), electron spin resonance (ESR), N2O titrations and the activities were evaluated for single step dimethyl ether (STD) synthesis from syngas. It is observed that the copper species were in highly dispersed state over Cu–ZnO–Cr2O3at high Zn/Cr ratios while the copper cluster were present at low Zn/Cr ratios. The ESR analysis revealed signals due to isolated Cu2+at high Zn/Cr ratios and clustered Cu2+at low Zn/Cr ratio in fresh catalysts and only Cr3+species in used catalysts. The TPR results indicated that the reduction peak shifted to high temperatures with an increase in chromium content due to large copper crystallites, which was supported by XRD analysis. The conversion of syngas to DME was well correlated with the copper metal surface areas, indicating that STD synthesis can be controlled by methanol synthesis rate.